Folding measuring instrument with improved linkage members

ABSTRACT

A folding measuring instrument has alternate pairs of bosses and grooves on each side of the pivot on each linkage member. Pairs of bosses are aligned with and fit into pairs of grooves but do not contact the bases of the grooves.

Umted States Patent [151 3,673,692 Quenot *July 4, 1972 [54] FOLDING MEASURING INSTRUMENT WITH IMPROVED LINKAGE MEMBERS References Cited [72] Inventor: Andre Quenot, Besancon, France I UNITED STATES PATENTS Assigneer Manufacture Quenot Mabo, Besanson, 496,123 4/1893 Keuffcl ....33 105 France l,907,459 5/l933 Stowell ....33/l05 Notice: The portion of the term of this patent sub- 25l5622 7/1950 20 sequent to g 5 1986, has been 3,458,937 8/l969 QUCIIOI ..33/l l8 claimed. Primary Examiner-Leonard Forman Filed: 1969 Assistant Examiner-Charles E. Phillips [21] APPL No: 886,872 Atmrney-Robert E. Burns and Emmanuel J. Lobato [57] ABSTRACT [30] Foreign Application Priority Data I A folding measuring instrument has alternate pairs of bosses Dec. 30, France and grooves on each side of the pivot on each linkage member. Pairs of bosses are aligned with and fit into pairs of U.S. l8, grooves but do not ontact the bases of the grooves [51] Int. Cl ....B43l 7/06, GOlb 3/06 [58] Field of Search ..33/ 105, l 18 2 Claims, 2 Drawing Figures PATENTEDJUL 4 1972 3, 673.692

FIG.2

INVENTOR:

I ANDRE QUENOT Attorney FOLDING MEASURING INSTRUMENT WITH IMPROVED LINKAGE MEMBERS This invention is an improvement in the folding measuring instruments incorporating improved linkage members described in U.S. Pat. No. 3,458,937 issued Aug. 5, 1969 to the applicant.

Referring to said patent, it will be seen that such a folding measuring instrument is composed of a series of graduated sections, said sections having adjacent ends provided with identical cooperating, resilient linkage members, said sections being pivoted together at said adjacent ends by a pivot passing through the center of said linkage members, said members having side flanges directed in one direction and gripping the side edges of said sections; said linkage members each having pairs of bosses and openings on each side of said pivot, a pair of openings on one side of said pivot being aligned with a pair of bosses on the other side of said pivot, said bosses being directed in the opposite direction as said flanges, said linkage members being superimposed on one another between adjacent sections and mounted on said sections in such a way that the bosses of one member engage in the openings of the other member.

It is an object of this invention to provide such a measuring instrument in which the strength of the linkage members is increased and in which the resistance to wear caused by folding and unfolding is reduced.

The invention will be better understood by referring to the following description, made by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a bottom view of the linkage member according to the invention.

FIG. 2 is a cross-section along line lI-II of FIG. 1.

The linkage member 1, conforming to that described in U.S. Pat. No. 3,458,937 is produced in synthetic material, and comprises at its center an orifice 2, to accommodate a rivet.

On either side of the orifice 2 are two pairs of rectangular grooves 3, 3, and 4, 4', each groove of one pair being separated from the other by a boss, as at 5 and 6. Of course, the complementary linkage-member (not shown) of the adjacent arm, will comprise two pairs of bosses separated by a groove.

Conforming to the invention, each groove 3, 3 and 4, 4', is provided with a thin base shown at 7, 7', and 8, 8, made during the molding or injection process with the linkage member.

The thickness of the bosses, such as at 5 or 6 of all the linkage members on an instrument is such that these bosses can penetrate into the corresponding grooves without coming directly into contact with the base.

The arrangement providing grooves with bases allows a notable increase in the strength of the linkage member to fully resist deformation in the plane of the linkage member by forces which act upon locking or unlocking of the complementary linkage members during the relative pivoting of the two arms of an instrument. Furthermore, the fact that the bosses do not fully penetrate into the grooves and do not contact the bases considerably reduces wear on the members thereby lengthening the useful life thereof.

It is also possible to provide an instrument in which each graduated section and its linkage members are moulded in a single piece from synthetic material.

What is claimed is:

1. A folding measuring instrument comprising a series of graduated sections, said sections having adjacent ends provided with identical cooperating resilient linkage members, said sections being pivoted together at said adjacent ends by a pivot passing through the center of said linkage members, said members having side flanges directed in one direction and gripping the side edges of said sections; said linkage members each having pairs of bosses and grooves on each side of said pivot, said grooves being provided with thin bases for strengthening purposes, a pair of grooves on one side of said pivot being aligned with a pair of bosses on the other side of said pivot, said bosses being directed in the opposite direction as said flanges, said linkage members being superimposed on one another between adjacent sections and mounted on said sections in such a way that the bosses of one member engage in the grooves of the other member without contacting the bases of said grooves.

2. A folding measuring instrument according to claim 1, wherein each section and its resilient linkage members are molded in a single piece from synthetic material. 

1. A folding measuring instrument comprising a series of graduated sections, said sections having adjacent ends provided with identical cooperating resilient linkage members, said sections being pivoted together at said adjacent ends by a pivot passing through the center of said linkage members, said members having side flanges directed in one direction and gripping the side edges of said sections; said linkage members each having pairs of bosses and grooves on each side of said pivot, said grooves being provided with thin bases for strengthening purposes, a pair of grooves on one side of said pivot being aligned with a pair of bosses on the other side of said pivot, said bosses being directed in the opposite direction as said flanges, said linkage members being superimposed on one another between adjacent sections and mounted on said sections in such a way that the bosses of one member engage in the grooves of the other member without contacting the bases of said grooves.
 2. A folding measuring instrument according to claim 1, wherein each section and its resilient linkage members are molded in a single piece from synthetic material. 